; =============================================================================
;
;                            Litos - Tree list
;
; =============================================================================

		CODE_SECTION	32

; ------------- Macro - initialized tree list entry

%macro		TREEHEAD 0
		LISTHEAD		; sibling list
		dd	NULL		; no children
		dd	NULL		; pointer to parent (NULL=none)
%endmacro

; ------------- Macro - initialize tree list entry (%1=tree list entry)

%macro		TREEINIT 1
		LISTINIT %1		; initialize sibling list
		and	dword [%1+TREE_Child],byte 0 ; no children
		and	dword [%1+TREE_Parent],byte 0 ; no parent
%endmacro

; ------------- Macro - add (initialized) tree list entry into tree list
; %1=parent, %2=tree list entry, %3 and %4=temporary registers

%macro		TREEADD	4
		mov	%3,[%1+TREE_Child] ; get a child
		or	%3,%3		; is any child?
		jz	%%L		; there is no child
		LISTADD	%3,%2,%4	; add new entry into sibling list
%%L:		mov	[%1+TREE_Child],%2 ; set new entry as new child
		mov	[%2+TREE_Parent],%1 ; link parent to new entry
%endmacro

; ------------- Macro - delete tree list entry from the list
; %1=parent, %2=tree list entry, %3 and %4=temporary registers

%macro		TREEDEL	4
		LISTDEL	%2,%3,%4	; detach from sibling list
		cmp	%2,%3		; is list empty?
		jne	%%L		; list is not empty
		xor	%3,%3		; invalid child
%%L:		mov	[%1+TREE_Child],%3 ; set new child

%endmacro

; -----------------------------------------------------------------------------
;                         Initialize tree list entry
; -----------------------------------------------------------------------------
; INPUT:	EBX = tree list entry
; -----------------------------------------------------------------------------

TreeInit:	TREEINIT ebx		; initialize tree list entry
		ret

; -----------------------------------------------------------------------------
;          Add (initialized) new tree list entry into tree list
; -----------------------------------------------------------------------------
; INPUT:	EAX = new tree list entry (must be initialized)
;		EBX = parent tree list entry
; -----------------------------------------------------------------------------

TreeAdd:	push	ecx		; push ECX
		push	edx		; push EDX
		TREEADD	ebx,eax,ecx,edx	; add new tree list entry into the list
		pop	edx		; pop EDX
		pop	ecx		; pop ECX
		ret

; -----------------------------------------------------------------------------
;                  Delete tree list entry from the list
; -----------------------------------------------------------------------------
; INPUT:	EAX = tree list entry to delete
;		EBX = parent tree list entry
; -----------------------------------------------------------------------------

TreeDel:	push	ecx		; push ECX
		push	edx		; push EDX
		TREEDEL	ebx,eax,ecx,edx	; delete tree list entry
		pop	edx		; pop EDX
		pop	ecx		; pop ECX
		ret